Wellbore reverse circulation with flow-activated motor

Abstract

A well system includes a work string extendable into a wellbore, and a pump that pumps a fluid into an annulus defined between the work string and the wellbore. A flow-activated motor is coupled to the work string and has a housing that receives the fluid pumped into the annulus. The flow-activated motor further includes a driveshaft rotatably positioned within the housing and a plurality of rotor vanes coupled to the driveshaft, wherein the driveshaft rotates as the fluid flows through the housing and impinges on the plurality of rotor vanes. A rotating agitator tool is coupled to the driveshaft such that rotation of the driveshaft correspondingly rotates the rotating agitator tool. The rotating agitator tool engages and loosens debris in the wellbore while rotating, and the debris is entrained in the fluid and flows through the flow-activated motor and subsequently to a surface location for processing.

What is claimed is: 
     
       1. A wellbore cleanout tool, comprising:
 a flow-activated motor having a housing, a driveshaft rotatably positioned within an interior of the housing, and a plurality of rotor vanes coupled to the driveshaft, wherein the driveshaft rotates as a fluid flows into and through the housing and impinges on the plurality of rotor vanes; 
 a rotating agitator tool coupled to the driveshaft such that rotation of the driveshaft correspondingly rotates the rotating agitator tool, wherein debris engaged by the rotating agitator tool while rotating is loosened and entrained in the fluid to flow through the flow-activated motor; 
 one or more bullnose ports defined in the housing to receive at least some of the fluid into the interior of the housing, the one or more bullnose ports being positioned axially between the rotating agitator tool and the plurality of rotor vanes; 
 one or more nozzle ports defined in the rotating agitator tool to receive at least some of the fluid; and 
 a fluid conduit defined in the driveshaft to conduct the fluid from the one or more nozzle ports to the interior of the housing, the fluid conduit extending to a portion of the driveshaft that is axially between the one or more bullnose ports and the plurality of rotor vanes. 
 
     
     
       2. The wellbore cleanout tool of  claim 1 , wherein the rotating agitator tool is a cutting tool selected from the group consisting of a drill bit, a reamer, a hole opener, a mill, a scrapper, and any combination thereof. 
     
     
       3. The wellbore cleanout tool of  claim 1 , further comprising one or more cutting elements arranged about an outer periphery of the rotating agitator tool. 
     
     
       4. The wellbore cleanout tool of  claim 1 , wherein the flow-activated motor is selected from the group consisting of a hydraulic motor, a vane motor, a turbine, a rotor-type motor, a stator-type motor, and any combination thereof. 
     
     
       5. The wellbore cleanout tool of  claim 1 , further comprising one or more bearing assemblies interposing the driveshaft and the housing to support the driveshaft in rotation. 
     
     
       6. The wellbore cleanout tool of  claim 1 , wherein the plurality of rotor vanes is arranged in a plurality of stages axially offset from each other along the driveshaft. 
     
     
       7. The wellbore cleanout tool of  claim 1 , further comprising a central conduit defined in the rotating agitator tool that fluidly communicates with the one or more nozzle ports, wherein the fluid enters the housing by flowing through the one or more nozzle ports, the central conduit, and the fluid conduit. 
     
     
       8. The wellbore cleanout tool of  claim 1 , wherein some or all of the plurality of rotor vanes is made of an erosion-resistant material. 
     
     
       9. The wellbore cleanout tool of  claim 1 , wherein some or all of the plurality of rotor vanes is clad with an erosion-resistant material. 
     
     
       10. A method, comprising:
 introducing a work string into a wellbore, the work string including a flow-activated motor having a housing and a driveshaft rotatably positioned within the housing and a rotating agitator tool coupled to the driveshaft such that rotation of the driveshaft correspondingly rotates the rotating agitator tool, the driveshaft being coupled to a plurality of rotor vanes; 
 pumping a fluid into an annulus defined between the work string and the wellbore with a pump; 
 receiving at least some of the fluid through one or more bullnose ports defined in the housing and into an interior of the housing, the one or more bullnose ports being positioned axially between the rotating agitator tool and the plurality of rotor vanes; 
 receiving at least some of the fluid through one or more nozzle ports defined in the rotating agitator tool, through a fluid conduit defined in the driveshaft, and into the interior of the housing, the fluid conduit extending to a portion of the driveshaft that is axially between the one or more bullnose ports and the plurality of rotor vanes; 
 impinging the fluid on the plurality of rotor vanes and thereby rotating the driveshaft; 
 rotating the rotating agitator tool and thereby engaging and loosening debris in the wellbore; and 
 entraining the debris in the fluid and flowing the debris through the flow-activated motor with the fluid. 
 
     
     
       11. The method of  claim 10 , wherein impinging the fluid on the plurality of rotor vanes comprises impinging the fluid on a plurality of stages axially offset from each other along the driveshaft, wherein each stage includes rotor vanes arranged circumferentially about the driveshaft. 
     
     
       12. The method of  claim 10 , further comprising:
 discharging the fluid and the debris entrained in the fluid from the flow-activated motor and into the work string; and 
 conveying the fluid and the debris entrained in the fluid within the work string to a surface location. 
 
     
     
       13. The method of  claim 10 , further comprising altering at least one of the geometry, the size, and the number of the plurality of rotor vanes to optimize operation of the flow-activated motor. 
     
     
       14. A well system, comprising:
 a work string extendable into a wellbore; 
 a pump that pumps a fluid into an annulus defined between the work string and the wellbore; 
 a flow-activated motor coupled to the work string and having a housing that receives the fluid pumped into the annulus, the flow-activated motor further including a driveshaft rotatably positioned within an interior of the housing and a plurality of rotor vanes coupled to the driveshaft, wherein the driveshaft rotates as the fluid flows through the housing and impinges on the plurality of rotor vanes; 
 a rotating agitator tool coupled to the driveshaft such that rotation of the driveshaft correspondingly rotates the rotating agitator tool, wherein the rotating agitator tool engages and loosens debris in the wellbore while rotating and the debris is entrained in the fluid and flows through the flow-activated motor; 
 one or more bullnose ports defined in the housing to receive at least some of the fluid into the interior of the housing, the one or more bullnose ports being positioned axially between the rotating agitator tool and the plurality of rotor vanes; 
 one or more nozzle ports defined in the rotating agitator tool to receive at least some of the fluid; and 
 a fluid conduit defined in the driveshaft to conduct the fluid from the one or more nozzle ports to the interior of the housing, the fluid conduit extending to a portion of the driveshaft that is axially between the one or more bullnose ports and the plurality of rotor vanes. 
 
     
     
       15. The well system of  claim 14 , wherein the work string comprises one of drill pipe lengths connected end to end or coiled tubing. 
     
     
       16. The well system of  claim 14 , further comprising a central conduit defined in the rotating agitator tool that fluidly communicates with the one or more nozzle ports, wherein the fluid enters the housing by flowing through the one or more nozzle ports, the central conduit, and the fluid conduit.